Method of making spinnerets



April 12, 1960 L. P. 0515 METHOD OF MAKINGSPINNERETS Original Filed May18, 1955 METHOD OF MAKING SPINNERETS Louis 1. Deis, Westtown, Pa,assignor to American Viscose Corporation, Philadelphia, Pa., acorporation of Delaware Original application May 18, 1955, Serial No.509,3?-

Divided and this application March 14, 1957, Serial No. 646,098

7 Claims. c1. 29-460 The invention relates to the method of makingspinnerets. Particularly, the inventionis concernedwith the method ofmaking self-cleaning spinnerets which are adapted to apply variousfinishing, colorant or additive solutions to the material extrudedthrough the capillaries or openings of the spinnerets. This applicationis a flitcd mates .Pat h D division of my United States Patentapplication 509,349 .5

will cause the solutions extruded therethrough to flow 5:1

as a viscous mass along the face of the spinneret, rather than beingextruded as a continuous strand or filament. This undesirable action onthe part of the extruded solutions disrupts the continuity of the fluidextruded through the other capillaries, necessitating the cleaning orreplacement of the spinneret itself.

Further, it is often desirable to have the extruded strand possess acertain finish, color, or other characteristic which is imparted to thefilament-forming solutions by the use of various additives or colorants.

Normally these additives and colorants are incorporated into the mixerin which the filament-formingsolution is first formed, or are intermixedwith the filament-forming solution after its formation and before itsextrusion through the spinneret. However, these known methods ofimparting desirable properties to the filamentary strand render itdifiicult to maintain control over the quality of the particularcharacteristic imparted to the filament and also lack flexibility, asfor example when filamentary strands having treated sections ofrelatively short length are desired. It is therefore an object of theinvention to provide a generally new or improved and more satisfactorymethod for making spinnerets having greater utility than thoseheretofore known.

Another object is to provide a method of making a spinneret havingcapillaries which may be flushed clean without removal of the spinneretfrom its operating position.

Still another object is the provision of the method of forming aspinneret having a porous internal structure through which flushing,colorant, and additive fluids may be forced to and through the capillarywalls.

A further object is the provision of a method of making a spinnerethaving an integral fluid supply chamber from which various flushing,colorant, or additive solutions may be forced through the porousinterior structure of the spinneret to the spinneret capillaries.

These and other objects and advantages of the invention will be apparentfrom the following description and accompanying drawing in which:

. 2,932,084 Patented Apn 12,1960

Fig. 1 is a top view of a spinneret made in accordance with the presentinvention;

Fig. 2 is a central vertical section taken on the lin II--II of Fig. l;

Fig. 3 is a fragmentary horizontal section, on an enlarged scale, takenthrough the wall of the spinneret along the line III-III of Fig. 2;

Fig. 4 is a section similar to Fig. 3 taken along the line I VIV ofFig.2; and

Fig. 5 is a fragmentary vertical section, on an enlarged scale,taken-through the face of the spinneret along the line V-V of Fig. 2. pH A spinneret made bythe method of the present invention resembles aconventional spinneret in shape, with the addition of a fluid receivingchamber or trough extend ing around its exterior periphery. The exposedsurfaces of the. annular wall and face of the spinneret, and walls ofthe'fluid receiving chamber are coated with a thin layer of imperviousmaterial, while the internal structure of the assembly is porous so asto permit the flow of I fluid therethrough. The spinneret openings orcapillaries are formed after the exposed surfaces have been coated,

so that the major portion of the capillary walls are defined by theporous structure of the spinneret face. Fluid under pressure is adaptedto flow freely from the chamber through the porous internal structure ofthe spinneret to the capillary walls to flush the same of any foreignmatter, or to be applied to the filament-forming material extrudedtherethrough.

As shown in the drawings, the spinneret has a conventional cup-shapedbody including an annular ortubular wall 11 and a face 13 integrallyformedby sintering a powdered material, as for example stainless steelparticles, under high temperature and pressure in a suitably shapedmold. Extending around the external periphery of the annular wall 11,adjacent to its inlet end, is a circular fluid receiving chamber ortrough 15 having a side wall 17 and a bottom wall 19, with the wall 19provided with a fluid inlet opening 21 defined by ,a collar 23. Anysuitable means, as for example external threads, may be provided on thecollar 23 to facilitate attachment of fluid conduit means thereto. Thewalls 17 and '19 are also fabricated by sintering, under hightemperature -and pressure, a powdered material of the same type asemployed in the spinneret body, and may be formed either integrally withthe spinneret body or as a separate unit, with the first'mentionedprocedure being preferable. The sintering procedure employed providesthe spinneret body'and chamber Walls with a strong but porous structure,as shown at 25, through which fluids, under pressure, are able to flow.The strength of these members and the rate at which they conduct fluidsmay be readily controlled by the particle size of the powdered materialand sintering temperatures and pressures.

The top of the chamber 15 is formed by an annular plate 27 fastened, ina fluid-tight manner, to the walls 11 and 17 of the spinneret assembly.The plate 27 need not be of porous construction and is preferably formedof a material, for example stainless steel, not readily attacked by thesolutions normally employed. All of the exposed surfaces of thespinneret assembly are then coated or plated with a thin layer 29 ofimpervious material, as for example stainless steel, while the inletopening 21 is temporarily sealed with a suitable stopper, after whichthe openings or apertures or capillaries 31 are formed in the spinneretface 13. By punching the capillaries 31 after the assembly has beencoated, it will be evident that the major portion of the capillary wallsare defined by the internal porous structure of the face 13. From thestructure described thus far, it is seen that fluid forced into thechamber 15, after its temporary seal is removed, is adapted to flowalong the porous internal *sfiucture ofthe"annulaflwall 11 and face/13to the capillaries--31, asshown-by the-arrows 33 and 35 in Figs. 4 and5, and is confined to its path by the impervious exposed surfaces 29 oneither side of the porous internal str uc'tu're. a

With regard to the walls 17 and 19 ofthe chainberlS, it= will be notedthat their internal surfaces remain "uncoated and therefore fluid fromthe chamber canfpass through these'walls to the wall 11 of thespinneret, in addition to the direct passage to the wall 11 as shown inFig. 4. The walls 17-and 19 of the chamber are preferably'sinteredsimultaneously with the wall and face of the spinneret sinceforming these elements as a unit separate-fro'm the 'spinneretbodyrequires extreme care *to' prevent blocking -of theporous structure ofthe wall 11 at the point of connection of the-walls 11 and 19.

In use; the fluid is forced by any suitable manner, not shown, through"the inlet opening 21 in'to the'chamb'er 15. Sufiic'ient pressure 'is'employedto' force the fluid as above "-described to the capillary wallsso -as;to"flu'sh the sameof anyforeign matter. After'fiushing,otherflu'ids'may be forced into the chamber 15 and-caused to flow alongthe wall-11 and the face 13 to-the capillaries, and impart-to thefilament-forming solutions extruded therethrough, any desirable finishor color. It is'seen that the additive fiu id" can be changedwhendesired without in any way stopping or altering the extrusion of thefilament-forming material-through the spinneret'capillaries, andthus thespinneret provides excellent flexibility when filaments of variouscharacteristics are-desired.

It is seen fromthe above description that'the objects 'of'the inventionarewell fulfilled by the method described. The description is intendedto be illustrative only and it --is-to be understood that changes" andvariations'may be made without departingfrom the spirit and scope of'theinvention as defined by the appended claims.

I claim: 1 1. A method of producing a spi'nn'eret forusein-making'filaments including the steps'of forming a cup-shaped'member having a porous fluid permeable structure, cover- :ing anexposed portion of the fluid permeable structure, "applying a fluidimpermeable coating on the remaining "exposed surfaces of the member toconfine the" fluid permeable structure of said member betweenapair oflessees-1.

"tion of said member may permeate through the confined portion of theporousstructure and at least surface-treat securing an annular covertothe trough over its open end, applying a fluid impermeable coating onexposed surfaces of the member toconfine. the porous structure of saidmember between a pair of fluid impermeable surfaces, and perforating acoated portion of the member with a plurality'of apertures extending inadirection approximately parallel to its axis whereby liquidfrom sa'idchannel-shaped -trough' may permeate through the confined porousStructure of said member and pass through the walls ofthe apertures toflush the same.

5. A method as defined in claim 4 wherein said porous fluid permeablestructure is formed by sintering metal powders under pressure.

6. A method as defined in claim 5 wherein said fluid impermeable coatingis metallic.

7. A method of producing a. self-cleaning spinneret for use in makingfilaments including the steps of form- .ing a-cup-likemembcr having aporous fluid permeable structure, applying an impermeable coating onexposed surfaces ofihe .member to confine the fluid permeable structureof-said member between a pair of fluid impermeable surfaces andperforating the coated member 'with' a pluralityof extrusionaperturesextending in'a direction approximatelyparallel to its axiswhereby liquid fluid impermeable surfaces, and perforating acoatedportion of the member with a plurality of apertures extending in adir'ectionapproximately parallel to its axis whereby liquid deliveredthrough the uncoated por- -delivercd tothe confined fluid permeablestructure of said member flows therethrough to the walls of theapertures for atleast surface-treating filament-forming material 'as itis extruded.

References .Citedin the file of this patent UNITED STATES PATENTS1,604,216 ..Brainin Oct. 26, 1926 1,093,800 May Sept. 21, 1937 2,307,034Gaenzle Jan.. .5, 1953

